There are methods of reducing dimensions of a feature vector used in pattern recognition as described below.
A first method is a method of reducing the dimensions from a high order to a low order by using a projection matrix obtained from learned data prepared in advance by an analysis of principal component. However, with the first method, a memory which is the square of dimensions for memorizing the projection matrix and a large capacity of memory and amount of calculation for a product-sum operation of the square of the dimensions for calculating the projection are required.
As a second method which does not require the large capacity of memory and amount of calculation, there is a method of reducing the dimensions by extracting components of the feature vector randomly. However, since this second method depends on the number of components that a recognition performance extracts, if the dimension reduction is performed significantly, the recognition performance is significantly reduced.
As a third method, there is a method of dividing the components of the feature vector into a plurality of sections, like an areal mean method as an image reduction method, and employing an average value of the respective sections as a component of the feature vector reduced in dimension. However, with the third method, if the correlation of the components to be averaged is high, the recognition performance is lowered.
With the methods of the related art as described above, there is a problem that the dimension reduction of the feature vector used in the pattern recognition can hardly be performed with a small capacity of memory and amount of calculation while maintaining the recognition performance.
Accordingly, in order to solve the problem described above, the embodiments disclosed here provide a pattern recognition apparatus capable of performing the dimension reduction of the feature vector used in the pattern recognition with a small capacity of memory and amount of calculation while maintaining the recognition performance, a method thereof, and a program product therefor.